US3257885A

US3257885A - Rotary panel cutter

Info

Publication number: US3257885A
Authority: US
Inventors: Helmut O Hornung
Original assignee: FL Smithe Machine Co Inc
Current assignee: FL Smithe Machine Co Inc
Priority date: 1964-06-19
Filing date: 1964-06-19
Publication date: 1966-06-28
Anticipated expiration: 1983-06-28

Description

June 28, 1966 H. o. HORNUNG 3,257,885

ROTARY PANEL CUTTER Filed June 19, 1964 2 Sheets-Sheet l A////SPiC/w Pefssu 4425/4' C .n fllllllIl/l, 11111111 1111111111111111111111111111/ l X//g/ Spec/nc P9535 z/PE ,425,0

June 28A, 1966 H. o. HoRNuNG 3,257,885

ROTARY PANEL CUTTER Filed June 19, 1964 2 Sheets-Sheet 2 @am mw P/m/ a5 'Tlc'.E-

T1 .B- J4 55 5! @"5 0% United States Patent O 3,257,885 ROTARY PANEL CUTTER Helmut O. Hornung, Scarsdale, N.Y., assiguor to F. L.

Smithe Machine Co., Inc., New York, NX., a corporation of New York Filed June 19, 1964, Ser. No. 376,449

8 Claims. (Cl. Sil- 346) l This invention relates in general-to cutting devices, and methods of making said devices. More particularly the invention relates to cutting knives for use in rotary panel cutters.

The present invention finds particularly utility in the manufacture of envelope blanks wherein blanks are advanced in succession into association with a panel cutting mechanism for cutting away a rectangular panel window, or in some instances a notch. The present invention is an improvement over devices of this character, particularlyin connection with the arrangement and method of construction of the cutting knife associated with the panel cutting mechanism.

In the past, one of the problems associated with uniformcutting clearance knives used in rotary panel cutting devices was that the uneven distribution of cutting pressure applied over the blade contact area causing premature dulling in the high pressure areas, or in the alternative incomplete serverance in the low pressure areas.

A novel cutter overcoming this problem is disclosed in U.S. Letters Patent, No. 3,106,121 having an assignee in Common with the present application. In the foregoing patent the edges of the end portions of the knife are ground on a radius larger than the radius between the axis of rotation of the panel cutter and the edges of the side portions -of the blade. This grindingV technique effectively increases the cutting clearance in the otherwise high pressure areas of the knife edge to equalize the pressure, and therefore wear, in that portion of the knife with the pressure and wear in the other portions of the knife edge. The present invention is an improvement overthat device, in that the desired uniform knifeedge cutting pressures. are obtained by a flexing of the cutting blade rather than as a result of a costly machining operation.

Accordingly,- it is an object of this invention to provide an improved rotary panel cutter.

A further object of this invention is to provide a rotary panel cutter utilizing a panel cutting knife designed to flex during the cutting operation. l

Another object of this invention is to provide a rotary panel cutter utilizing a cutting knife having portions thereof preexed to a desired radius.

A further object of this invention is to provide a flexible cutting knife.

A further object of the invention is to provide a low cost method for the production of cutters comparable in performance to cutter of the aforementioned U.S. Letters Patent.

Other objects and a fuller understanding of the invention may be had by reference to the following descripv tion and drawings, in which:

'l base by an adhesive 53 or other suitable means.

3,257,885 Patented June 28, 1966 ting edges have an effective radius larger than the radius from'the center of the mounting support roller to the side cutting edges;

FIG. 5 is an enlarged partial cross-sectional view of the cutter of FIGS. 3 and 4 taken on line 5 5 of FIG. 4;

FIG. 6 is a top plan view of a second embodiment of the invention FIG. 7 is a cross-sectional view of the cutting knife of FIG. 6;

FIG. 8 is a view similar to FIG. 7 showing another embodiment of the invention;

FIG. 9 is a view similar to FIGS. 7 and 8 showing still another embodiment of the invention; Y

FIG. l() is a greatly magnified diagrammatic view,l indicating the relative areas of low and high contact pressure between the cutting knife and the anvil roller when the axis of the knife is parallel to the roller axis; and

FIG. 11 is a view similar to that shown in FIG. 10 indicating how the relative size of the cutting areas of the knife when mounting skew to the axis of rotation of the anvil backing roller.

With reference to the drawings, the invention as illustrated as being incorporated in a rotary panel cutter as shown generally in FIG. 1. As illustrated, the rotary panel cutter includes a lower rotary panel cutting mechanism 20, and upper cooperating backing anvil roller 22. Envelope blanks 24 are fed in succession through the rotary panel cutter by means of a pair of conveyors 26 and 28. The conveyors 26 and 28 are provided with upstanding aligning pins 30 and 32 which move behind and engage the notches in the trailing seal flap 34 of the envelope blank 24, and accurately align each blank prior to its passage through the panel cutting mechanism 20. The aligning pins 30 are arranged to feed the blank 24, at a small angle offset from the direction of feed. The panel cutting mechanism 20 includes a central vacuum and pressure controlled cylinder 36 rotationally supported on a shaft 37. The shaft includes a hollow central passageway 39 which communicates with a tube 38 to a source.

of negative pressure or vacuum (not shown). The passageway 39 is selectively placed in communication with either

tube

38 or 40 by a well known type of rotary to control the periods at which the central passageway 39 is subjected to either negative or positive pressure. An elongated radial passage 44 places the passageway 39 in communication with a pair of small openings 46 in one of a pair of panel cutting mounting shells 48. The semicircular shells 48 are aligned in position over the cylinder 36 and clamped thereon by bolts 50.

One embodiment of the invention is shown in detail in FIGS. 2 to 6. Referring first to FIGS. 2, 3 and 6, the panel cutting knife includes a continuous rectangular blade 52 which is positioned on a curved surface of a mounting base 54. The blade may be secured to the The blade 52 and base 54 assembly, hereafter called the cutting knife is in turn `secured to the mounting shell 48 by means of bolts 56, 58 and 60, said cutting knife being displaced from the surface of the mounting shell 48 by a spacer or shim 62. The shim 62 is rectangular in shape and of a length substantially less than that of the cutting knife. Theshim .62 is centrally positioned along the length of the cutting knife so that the extremeends of the cutting knife overhang the ends of the shim 62. Bolt 58 is seated in the center of the cutting knife and passes through the shim 62. Bolts 56 and 60 are seated in respective opposite ovcrhanging end portions of the cutting knife. The passageways 46 in the shell 48 communicate with apertures 64 in the shim 62. The apertures 64 communicate with a plurality of control apertures 66 which are eifective tov placethe positive or negative pressure of passage-v 3 way 39 to the interior confines of the panel cutting knife 52 (see FIG. 2).

FIG. 10 illustrates the relative pressures applied by the backing roller 22 on the cutting knife during a typical panel cutting operation when mounted with its axis par- Y allel to the shaft 37. It can be seen that the contact area of the side portions of the cutting knife is substantially greater than that of the end portions of the cutting knife, with a resulting low and high specific cutting pressures respectively. As pointed out in U.S. Patent, No. 3,106,- 121 and illustrated herein in FIG. l1, the cutting knife is usually mounted with its longitudinal axis slightly offset from the axis of the backing roller 22 to obtain a progressive sheared cut of the envelope blank 24. While offsetting the cutter in this way accomplishes a small degree of balancing of the cutting pressures between the side and end portions of the cutter, the longer side portions of the knife are nevertheless subjected to much less force per unit area of contact (pressure) than the ends of the knife, and hence the side portions will not dull as rapidly as the end blade portions.

In accordance' with one embodiment of the present invention, this uneven cutting pressure and wear of the blade edges is rectified by the use of the overhanging cutting knife, shim and bolt mounting arrangement described above. Bolts 56 and 60 are stressed sufficiently to impart a downward deformation of the cutting knife so that the end portions of the blade edge have more clearance with the backing roller 22 during its rotation than the relatively undeformed side portions of the blade have with respect to backing roller 22. This relationship is illustrated in enlarged scale in FIGS. 4 and 5. The rotation radius is referenced to the side portions of the blade 52 and compared with the new flexed radius of the blade 52 end portions. The increased clearance at the end edge portions result in a decrease in the force applied to the blade edge contact area. This force reduction in the small contact area end portion of the knife is therefore effective to substantially equalize the cutters pressure over all portions of the knifeedge.

Obviously due to the exing of the blade 52, during a panel cutting operation the side blade edges will penetrate deeper into the envelope blank 24 that the end blade edges. Therefore the angle of liex imparted to the cutting knife by tightening bolts 56 and 60 and the subsequent reduction in end blade edge cutting force is limited by the thickness of the envelope blanks 24 to be cut, the proximity of the backing roller 22 to the cutting blade and the minimum depth of penetration by the blade edge that is necessary to completely sever a panel from the blank 24. It should be noted that cutting of the panel window from the blank material is brought about by crushing and compressing the blank 24 between the edges of the cutting knife and the backing roller 22 to a point of separation through embrittlement of the bers by pressure alone. A penetration of sixty percent or more of the thickness of the blank 24 will be suicient to bring about this result. A small clearance, slightly less than the thickness of the stock being cut, is therefore maintained `at all times between the knife and anvil roller 22.

In each of the embodiments a pair of annular rings 55 of resilient material are located adjacent the ends o-f the cutter 52 and rotate therewith. The rings S5 serve to tightly grip the envelop blank as they are fed through the panel cutter thereby insuring cutting registration accuracy.

In FIG. 7 another embodiment of the invention is shown very similarto FIGS. 3-5. FIG. 7 differs therefrom only in that it includes an integral shim portion 62a formed on the underside of base 54a. In all other respects this embodiment is the same as FIGS. 3-5 will be readily understood by those skilled in the art in view of the foregoing desoription of FIGS. 3-5.

Another embodiment of the invention is illustrated in FIG. 8. Here a modified -mounting shell 68 is recessed at 69, so as to form a raised support 72 or integral shim beneath the knife mounting block 70. The blade 74 is secured to the upper surface of the mounting base 70 by adhesive and the blade 74 and mounting base 70 assembly (hereafter called the cutting knife) centrally positioned over the raised support 72. In this embodiment the cutting knife is secured directly to the .raised support 72 by one or more bolts 76. Flexing of the cutting knife with the resulting decrease in specific pressure at the end portion of the blade 74 is accomplished during the cutting operation by the natural flexing of the overhanging end portions of the cutting knife when pressure -is applied by the backing roller 78. The amount of cutting knife exure in this embodiment is a function of the stiffness of the cantilevered end portions of the blade and the applied cutting force. Obviously, if the blade ends are made yieldable in this manner, the cutting pressures about the knife periphery will also be essentially equalized with the result that equal wear will be obtained.

'FIG. 9 shows another embodiment of the invention wherein a blade 78 is mounted on a ba-se 80 as in the previous embodiments. Here the cutting knife assembly is mounted on a pad 82 made of rubber or other yieldable material.A The knife and pad 82 are secured to the mounting shell 84 by three equally spaced and centered bolts 86. In this embodiment of the invention, the concentrated application of force over the small cutting area of the blade ends when the blade comes in contact with the backing roller 88 causes a larger degree of exure in this area to also equalize the cutting pressure about the blade periphery.

While various embodiments of the invention have been shown and described in detail to illustrate the'application of the invention principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A rotary cutter comprising rotary support means, knife means having at least one side blade portion substantially parallel tothe axis of rotation of said support means, and at least one end blade portion extending substantially transverse to the axis of rotation of said support means, and means for rigidly mounting said knife means to said support means, said mounting lmeans including means disposed intermediate to said knife means and said support means, said intermediate means being of shorter length than said side blade portion and fastening means exterior of the ends of said intermediate means for reecting the end Iblade portion closer to the support means axis of rotation than said side blade portion.

2. A rotary cutter according to claim 1 wherein said intermediate means is a Shim.

3. A rotary cutter according to claim y1 wherein said knife means includes a mounting block and means to secure said blade portions to said mounting block.

4. Rotating apparatus for cutting panels from blanks of sheet material comprising a cylindrical mounting means having an axis of rotation, knife means having a substantially rectangular outline and including end blade portions extending generally transverse to the axis of rotation of said cylindrical mounting means, elongated side blade portions extending generally parallel to the axis of rotation of said cylindrical mounting means, a mounting block and means to secure said .blade portions to said mounting block, intermediate means for rigidly mounting said knife means to said cylindrical mounting means, said intermediate means being disposed intermediate to said knife means and said cylindrical mounting means and being of shorter length than said side blade portions, fastening means exterior to the ends of said intermediate means for deecting the end blade portions closer to the cylindrical mounting means axis of rotation than said side blade portions, and an anvil roller cooperating with said knife means and arranged with its outer surface spaced a predetermined distance therefrom.

5. Rotating apparatus according to claim 4 wherein said intermediate means is a shim.

6. A knife for use in'rotary panel cutters comprising blade means and supporting base means, said blade means including at least one side blade portion and at least one end blade portion extending substantially transve-rse to and in the plane of said blade portion, said supporting base means having at least Ione pair of opposite surfaces, said blade means extending upward from and affixed to one of lsaid surfaces, said blade means terminating in a parallel to the `one of said surfaces, and the opposite surface substantially undercut inwardly so as to leave knife portions that can flex.

7. A knife for use in rotary panel cutters comprising a substantially rectangular blade and supporting rectangular base portion, said blade cooperating with one surface of said base portion and having cutting edges substantially perpendicular to the plane of the one surface of said base portion, with said cutting edges terminating in a plane parallel to said one surface of said base portion, said base portion having an opposite surface substantially overhangingA undercut inwardly so as to leave overhanging knife porknife means, said knife means including at least one side Iblade portion extending substantially parallel to the axis of rotation of said support means and at least one end blade portion extending substantially transverse to the axis of rotation of said support means, said mounting means including intermediate ,me-ans being positioned intermediate to said kn-ife means and said support means, said intermediate means being of shorter length than said side blade portion and fastening means interior to the ends of said intermediate means for fastening said support means and said knife means to said mounting means, said intermediate means being suiciently short in length so as to allow the end blade por-tions of said knife means to deflect in the direction of the axis of rotation of said support means due to the operating cutting pressures applied to said end portion of said knife means during operation.

References Cited by the Examiner UNITED STATES PATENTS 461,600 10/1891 West 83-348 844,171 2/ 1907 McAuulty 83-348 1,978,136 10/1934 Kavle 83-346 X 2,682,306 6/ 1954 Schriber 83--346 3,106,121 10/1963 Novick 83-346 X WILLIAM W. DYER, JR., Primary Examiner.

J. M. MEISTER, Assistant Examiner.

Claims

1. A ROTARY CUTTER COMPRISING ROTARY SUPPORT MEANS, KNIFE MEANS HAVING AT LEAST ONE SIDE BLADE PORTION SUBSTANTIALLY PARALLEL TO THE AXIS OF ROTATION OF SAID SUPPORT MEANS, AND AT LEAST ONE END BLADE PORTION EXTENDING SUBSTANTIALLY TRANSVERSE TO THE AXIS OF ROTATION OF SAID SUPPORT MEANS, AND MEANS FOR RIGIDLY MOUNTING SAID KNIFE MEANS TO SAID SUPPORT MEANS, SAID MOUNTING MEANS INCLUDING MEANS DISPOSED INTERMEDIATE MEANS BEING OF SHORTER SUPPORT MEANS, SAID INTERMEDIATE MEANS BEING OF SHORTER LENGTH THAN SAID SIDE BLADE PORTION AND FASTENING MEANS EXTERIOR OF THE ENDS OF SAID INTERMEDIATE MEANS FOR REFLECTING THE END BLADE PORTION CLOSER TO THE SUPPORT MEANS AXIS OF ROTATION THAN SAID SIDE BLADE PORTION.